The quality of drilled holes depends on the workman in question, since systems are used that are in part unstable, or the drilled holes are introduced completely freehand.
In some applications, automated drilling machines may be used. However, for various reasons, for example, due to factors such as the accessibility of the drilling location, the weight of the automated drilling machine, as well as on-the-job safety, this solution finds only very limited use.
From DE 2 238 838, a portable drilling and milling device of known art, which is designed for the manufacture of drilled holes, cut-outs, plane surfaces, or the like is disclosed. It includes a feed device, which tracks a drill according to the drilling progress, gearing to drive the drive shaft, an electrical controller for the control of the device, and means for retention and alignment on a plane, concave or convex surface of a component to be machined, and also at least three feet which at their lower ends are provided with suction cups, into which a vacuum may be introduced for attachment to a component to be machined.
However this device may be complicated to handle, so that this may lead to time-consuming manufacture in the production of individual parts.